The NT Department of Health and Families (DHF) has issued a warning for the potentially fatal Murray Valley encephalitis virus disease for the whole of the NT.
Recent evidence from sentinel chicken testing carried out by the Berrimah Farm Veterinary Laboratories in Darwin indicated the start of the Murray Valley encephalitis virus season.
Historically, February to June is the peak period for Murray Valley encephalitis virus activity in the NT.
Centre for Disease Control Director Dr Vicki Krause said the virus is transmitted by the bite of the common banded mosquito and potentially by the floodwater mosquito.
"These mosquitoes breed in flooded grassy and swamp areas and high numbers of the common banded mosquito will persist over the early dry season near the longer lasting swamp areas.
"The common banded mosquito bites after sundown, with a peak in the first two hours of the night. The floodwater mosquito also bites during daylight in shaded areas.
"Numbers of the common banded mosquito occur in relatively high numbers during and immediately after the wet season. Numbers are presently elevated in the Top End coastal regions and high in the recently flooded Barkly region," she said.
Only about one person in 1000 who gets bitten by infected mosquitoes will contract the disease. There are usually up to two MVE cases in the NT each year, with the last case reported in 2005.
And Dr Krause said that although people most at risk are those with no prior exposure to these viruses such as babies, young children, tourists or people from southern Australia, long-term residents are also at risk.
"Usual symptoms of Murray Valley encephalitis virus disease include severe headache, high fever, drowsiness, tremor and seizures - especially in young children. In some cases the condition progresses to delirium and coma which, in turn, lead to paralysis, brain damage, and a 25 per cent chance of death.
"People experiencing the early symptoms of the disease should seek urgent medical attention," said Dr Krause.
The warning particularly applies to people visiting or living in rural areas within five kilometers of river and creek systems throughout the risk area, especially at night. The risk is likely to be highest near seasonal and temporary wetlands, coastal brackish swamps, billabongs, river floodplains and heavily vegetated dams and drains.
Particular risk areas will be around the large coastal and sub-coastal flood plains and swamps associated with the large rivers, including the East and South Alligator, Mary, Adelaide, Howard, Finniss, and Daly Rivers. However, the risk also extends to other mosquito-prone areas, especially the Barkly region.
Urban residential areas within five kilometers of swamps and wetlands or other areas with poor drainage or creeks are also at risk, particularly when mosquitoes are causing pest problems.
There is no need to avoid travel to the risk region if normal mosquito self-protection is observed.
People are advised to take extra precautions in the risk region against being bitten by mosquitoes until the end of June when virus activity is expected to return to a minimum.
Precautions against being bitten by mosquitoes include:
- Avoid outdoor exposure from dusk and at night in risk areas and all areas of high mosquito activity.
- Ensure all insect screens are installed and mosquito proof. Use mosquito nets and mosquito-proof tents at night in all areas when camping or in unscreened areas.
- Wear protective light-coloured clothing with long sleeves, long trousers and socks between dusk and dawn.
- Use a protective repellent containing di-ethyl toluamide (DEET) or picaridin as a supplement to protective clothing when outdoors at night in areas of mosquito activity. The most effective and long-lasting formulations are those in lotions or gels. Most natural or organic repellents are not as effective as DEET or picaridin.
- Ensure children are adequately protected against mosquito bites.
Media contact: DHF Media Liaison OfficerCameronJackson, 0401 116 144
Release date: 29 January 2009
